Farm implements which are adapted to allow the outer wings to fold and trail behind the towing implement for narrow transport width are a widely used form of agricultural drawbar. The most economical form of these drawbars rely on the power source to tow the drawbar forward to fold the wings into transport position and to push the drawbar rearwardly to unfold the wings into the working/operating position.
To fold the wings, the operator must first disable the wing latching mechanisms, usually by means of a mechanical cable attached to a latch. Thereafter, the operator will drive forwardly with the power source, for example a tractor, until the wings trail behind the power source for transporting the implement on roads, highways, or through farm gates.
Proper trailing of the wings in transport position relies on one wheel on each wing being moved into a position parallel to the longitudinal axis of the wing. The same wheel should be perpendicular to the wing or be free to follow in the direction of travel when in the working position. As a result of these constraints, this wheel, typically a castering wheel, must change position as the wings are folded back to the transport position. Problems can arise when the wheel does not rotate into the proper transport locked position as the drawbar is towed or driven forward a short distance.
In order to unfold the wings from the transport trailing position to the operative unfolded working position, the operator must move the drawbar rearwardly until the wings spread out fully into the working position and the wing hitch latches are locked.
The prior art devices and method of inducing the wings to spread is to have the locked caster wheels cambered outwardly or with a positive camber such that their rolling path of least resistance is an arc which causes the wings to spread. Problems frequently arise when the ground surface is uneven or inclined because the natural tendency of the wheels to follow an arc is overpowered by external forces.
It is an object of the present invention to provide a castering wheel arrangement which improves the folding movement of the drawbar to the transport position.
It is a further object of the present invention to provide another castering wheel assembly which improves the speed and shortens the distance required to move the drawbar from the folded transport to the unfolded operating position.